Regarding a power conversion apparatus having a relatively large capacity, it is desired for suppressing a surge voltage applied to a switching device that is turned off to reduce not only an inductance component of a main circuit but also a total inductance component including an inductance component between a semiconductor device module and a filter capacitor as much as possible. Therefore, in a conventional power conversion apparatus, such a configuration that a multi-layer bus bar in which a plurality of conductors are stacked through an insulator is used as a conductor for connecting between the semiconductor device module and the filter capacitor is often used (Patent Literature 1, for example).
One of the representative multi-layer bus bars is a laminated bus bar in which an external surface of the bus bar is coated with a laminate material such as a plastic film.